Annual growth records from tress at Banma region in the southeastern Qinghai Plateau are correlated positivly with variations of summer precipitation and used to reconstruct the regional precipitation variation in the past.In a series of tests,it is shown that the relationship between the climate and tree ring variables is statisticlly significant and stable with time,confirming the power of dendroclimatic reconstruction in arid and semi arid region such as the south eastern Qinghai Plateau.